The invention discloses a small-size beam controllable
patch antenna based on a reconfigurable
parasitic element, and the antenna comprises an E-shaped main
radiation patch, a left parasitic patch anda right parasitic patch. Through employing a CSRR structure, the antenna reduces the
electrical length of a parasitic patch, and facilitates the
miniaturization of the parasitic patch. A
PIN diode isadded to CSRR structure for providing different
DC bias voltages, thereby enabling a single
parasitic element to work at two states: a director and a reflector. The combination of different states ofthe left and right parasitic elements can enable the
main lobe direction of a
radiation beam of the antenna to be switched among 0 degree, -30 degree, and 30 degrees, thereby achieving the beam controllable performance of the antenna, and effectively enlarging the
beam scanning range of the antenna. The antenna employs the coaxial feed E-shaped main
radiation patch and introduces an
air layer structure between two
dielectric substrates, thereby effectively enlarging the work bandwidth of the antenna. The antenna is high in
gain, is high in front-to-rear ratio, and is low in profile.